first to relieve stress and negative thoughts is to stop thinking for a moment, relax, empty your mind and begin to refill with a focus on finding the most sensible way out of the existing state.
Define specific objectives. "Being a positive person" is a very good goal, but this goal is too big. You yourself may be confused where to start. Therefore, try to set specific smaller goals, such as "Meditate twice a week" or "Smile to others once a day".